I downloaded Mozilla Firefox and I am trying to open it but I can't, I am currently using IE?

I am trying to open Mozilla Firefox but it doesn't let me. I just downloaded. I am used to using IE. What can I do to open Mozilla Firefox, can you walk me through this because I am new. Thanks

I downloaded Mozilla Firefox and I am trying to open it but I can't, I am currently using IE?windows server 2003

download firefox as a file, ie select save rather than install

then install it from the file.

when it asks to put icon on the desktop let it do it.